Nutrient Separations Systems: Current Progress and Future Opportunities

s energy, environmental, supply chain, and economic risks escalate in today's linear fertilizer manufacturing processes, there is an interest in developing technologies that enable a circular nitrogen-based fertilizer economy. Achieving this goal requires significant advancements to wastewater treatment, with a specific focus on the design of technologies and complete systems that can capture and recycle waste nutrients into usable fertilizers. Every year, millions of tons of nitrogen and phosphorus remain untapped in global municipal and industrial wastewater, presenting a significant opportunity for fertilizer utilization. Herein, we explore current and future opportunities for nutrient recovery systems to provide recycled fertilizers for agricultural use. We first quantify recoverable nutrient wastewater sources, examine current nutrient management processes (e.g., nitrification-denitrification, EBPR), and highlight performances and limitations of current nutrient management processes. We also review the current commercialization landscape for nutrient recovery systems and detail efforts made in advancing full-scale deployments. Finally, we review emerging electrified technologies and compare nutrient recovery technologies in terms of technology readiness, scalability, and environmental trade-offs. A gap analysis is also conducted to guide future research and development efforts in nutrient recovery.